iter:   1 x =    162.76857898  10739059.23031948      1.10107134 |f(x)| = 20.4037
          dx =     -0.25345191 -195704.17835643      0.11771325
status = iteration is not making progress towards solution
iter:   2 x =    162.76857898  10739059.23031948      1.10107134 |f(x)| = 20.4037
          dx =     -0.00000051     -0.21429092      0.00000018
chisq/dof = 24.4889

do
{
    iter++;
    status = gsl_multifit_fdfsolver_iterate (solver);

    if(verbose)
    {
        printf ("status = %sn", gsl_strerror (status));
        print_state (iter, solver);
    }

    // detect an error:
    if (status)
    {
        ret = false;
        break;
    }

    status = gsl_multifit_test_delta (solver->dx, solver->x, 1e-4, 1e-4);
}
while (status == GSL_CONTINUE && iter < 1000);

deriv = 0.14451 , 1.36748e-05 , -0.922072

iter:   1 x =    162.76857898  10739059.23031948      1.10107134 |f(x)| = 20.4037
          dx =     -0.25345191 -195704.17835643      0.11771325
|f(x)| = 20.4037
|f(x+dx)| = 21.512